UNIT Files. Procedure/Functionand Other Declarations (CONST, TYPE, VAR) can be stored under different Object Pascal Files (Library).

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1 Basics of Language UNIT Files Basics of Language UNIT Files UNIT Files Procedure/Functionand Other Declarations (CONST, TYPE, VAR) can be stored under different Object Pascal Files (Library). You can reduce the complexity by storing the things in unit files. 1

$Basics of Language UNIT Files unit Unit_Name; { unit Identifier} interface uses unit1,.$

2 Basics of Language UNIT Files unit Unit_Name; { unit Identifier} interface uses unit1,..., unit_n; {Other Unit Files to be used from within this unit} { Declaration Block} implementation {Detailed procedures and functions whose headers have been given in declaration block} end. Basics of Language UNIT Files Use the function called To_caps by storing the function into a unit file called first_unit. 2

Interface Part: Headers for functions and procedures Implementation Part: Details of Procedures

3 Basics of Language UNIT Files Use the function called To_caps by storing the function into a unit file called first_unit. Interface Part: Headers for functions and procedures Implementation Part: Details of Procedures and Functions defined in the header. Basics of Language Use of UNIT File UNIT Files By using uses unitname All procedures and functions are available now in main program 3

You can convert dfm files into text format using statement convert -t frmmain.

4 Basics of Language UNIT Files Each form and related source code within the project are stored in unit files. DFM Files are used to hold the objects within the forms of project. You can convert dfm files into text format using statement convert -t frmmain.dfm Filename for dfmfile Basics of Language Project File (under firstproject directory) UNIT Files Unit Files in Project Project files take the extension of dpr 4

5 Basics of Language Unit1 File in Project UNIT Files Basics of Language Unit2 File in Project UNIT Files 5

6 Basics of Language Sample Program in Twoforms directory UNIT Files Show and Showmodal are two different types of calls Basics of Language OBJECT ORIENTED PROGRAMMING 6

7 Basics of Language Object Orientation What is Object? An object is a data type which contains both data and methods (procedures and functions) to handle this data. Basics of Language Object Orientation Object Sample Person Name, Surname, Birth Date, Education etc. CalculateAge, EnterSurname Student Student Number, First Registration Date etc. CalculateGPA Staff Title, Expertise etc. FindExpertise Employee Starting date, Department etc. ProcessSalary Other Staff Position Type CalculateHorlySalary 7

8 Basics of Language Object Orientation Features of Object Oriented Programming 1. Inheritance 2. Encapsulation (Combining data and methods procedure/function within the same class or data structure) 2. Polymorphism Basics of Language Object Orientation Borland Pascal Compiler (Turbo Pascal) had object-oriented architecture before Microsoft C and Borland C compilers. 8

9 Basics of Language Object Orientation Under oop directory Basics of Language Object1 under oop directory Object Orientation PERSON Name Surname Birth Date Gender EMPLOYEE FBadgeNumber NameofSpouse EnterBadgeNumber ACADEMIC EMPLOYEE Title 9

Basics of Language Object Orientation Three features of Object Oriented Programming Inheritance TCircle=Class(TGeometricShape) Parent Class is TGeometricShape Encapsulation Diameter (data) and

10 Basics of Language Object Orientation Three features of Object Oriented Programming Inheritance TCircle=Class(TGeometricShape) Parent Class is TGeometricShape Encapsulation Diameter (data) and CalculateArea (method) are combined under same data type. Polymorphism Multiple use of same method under different children (CalculateArea) Basics of Language Main Program Object Orientation 10

11 Three features of Object Oriented Programming: Encapsulation TGeometricShape= Class ObjectName:string; Area:real; Procedure CalculateArea; end; Encapsulation is the data type which combines Data and Methods in the same structure Here; Data are ObjectName and Area Method is CalculateArea Three features of Object Oriented Programming: Inheritance TGeometricShape=Class ObjectName:string; Area:real; Procedure CalculateArea; end; TRectangle=class(TGeometricShape) Height,Width:real; Procedure SetDimensions(h,w:real); Procedure CalculateArea; end; By means of inheritance all data and methods are inherited by child class (object). TRectangle object herein inherits data and methods in TGeometricShape 11

Three features of Object Oriented Programming: Inheritance TRectangle object herein inherits data and methods in TGeometricShape ObjectName and Area are data inherited from TGeometricShape Three

12 Three features of Object Oriented Programming: Inheritance TRectangle object herein inherits data and methods in TGeometricShape ObjectName and Area are data inherited from TGeometricShape Three features of Object Oriented Programming:Polymorphism Polymorphism Multiple use of same method under different children (CalculateArea) Shape is Circle Now Shape is Rectangle CalculateArea calculates the area depending on the Shape of the object 12

access to a Private member from other modules Public members can be accessed

13 Basics of Language Object Orientation A TForm object with TButton object on top Basics of Language Object Orientation Source code for Form object You cannot access to a Private member from other modules Public members can be accessed from everywhere. Protected members can be accessed from descendant (child) objects. 13

14 ; Objects (Classes) Used to write Windows and Linux Applications VCL components are used to write Windows Applications and CLX components are used to write Linux Applications. VCL Visual Component Library CLX Cross-platform Library Extensions Whether they are VCL or CLX components, There are two types of them; 1. Visual Components 2. Non-Visual Components VCL and CLX components are like ActiveX (OCX) Components. However, they are better than OCX components in many aspects. For example, they are embedded into the executable file and They do not need to be registered. 14

15 Visual Components Visual Components Components which are visible during design and run-time. Examples; TButton, TEdit, TLabel etc. Non-Visual Components Non-visual Components Components which are visible only during design time and available with their functions during run-time. Examples; TTimer, TTable Components. 15

16 Object Inspector Window OBJECT INSPECTOR Used to change the properties of during design time. The properties and events for the selected component are displayed in this window. Object Inspector Window OBJECT INSPECTOR: Properties Page 16

17 Object Inspector Window OBJECT INSPECTOR : Events Page Object Inspector Window Properties for TButton Events for TButton 17

Events Each component (visual or non-visual)

(such as when Game Help clicking mouse or

Example; Suppose you have written a procedure

18 Events Each component (visual or non-visual) has got properties and events. Events: Activating methods Mine Field (procedures/functions) under certain events (such as when Game Help clicking mouse or pressing a certain key. Example; Suppose you have written a procedure which will activate when clicking on a Button object. The related procedure will be executed when user presses on that button. Events Message is displayed when the button is pressed. 18

19 Events Events1 dizinindeki Sample Program The procedure above is executed when user Presses button Component Pallette Components are placed under different pallettes. Components with different palettes are shown in the following slides. 19

20 Frames: Frame is a container for components; it can be nested within forms or other frames. MainMenu: Used to construct Pull Down menus PopupMenu: Used to construct or Pop up menus Label: is a nonwindowedcontrol that displays text on a form Edit: Edit is a wrapper for a Windows single-line edit control. Memo: a Windows multiline edit control. Button: Button is a push button control. Users choose button controls to initiate actions. CheckBox: A CheckBox component presents an option for the user. The user can check the box to select the option, or uncheck it to deselect the option. RadioButton: Radio buttons present a set of mutually exclusive options to the user that is, only one radio button in a set can be selected at a time. When the user selects a radio button, the previously selected radio button becomes unselected 20

21 ListBox: Use TListBox to display a scrollable list of items that users can select, add or delete. ComboBox: ComboBox combines an edit box with a scrollable list. ScrollBar: ScrollBaris a Windows scroll bar, which is used to scroll the contents of a window, form, or control. GroupBox: The TGroupBox component represents a standard Windows group box, used to group related controls on a form. When another control component is placed within a group box, the group box becomes the parent of that component. RadioGroup: A TRadioGroup object is a special group box that contains only radio buttons. Radio buttons that are placed directly in the same control component are said to be grouped. When the user checks a radio button, all other radio buttons in its group become unchecked. Panel: Panels have properties for providing a beveled border around the control, as well as methods to help manage the placement of child controls embedded in the panel. ActionList: Use Action lists to centralize the response to user commands (actions). 21

22 Sample Program in frame directory Frames: TFrame is a container for components; it can be nested within forms or other frames. Note: Autosize property for each frame is set to true Frames Sample Program in frames directory 22

23 TLabel Sample Program in button1 directory TEdit TButton TLabel Sample Program in button2 directory TEdit TButton 23

button, the combination of three colours; red, green and blue

24 TRadioGroup Sample Program in button3 directory TEdit TButton TLabel Sample Program in labels directory When you press Paint button, the combination of three colours; red, green and blue is randomly constructed and rectangle is painted with that colour. 24

25 Sample Program in Button_label directory const c1 = 32; c2 = 5; c3 = 9; TEdit Look at Sample Programs in Edit, edits, edits1 directories 25

26 Sample Program in button2 directory Sample Program in Buttons_runtime directory 26

27 Sample Program in mainmenu directory PopupMenu Sample Program in popupmenu directory Popup menu is activated when right Mouse button is pressed 27

28 Memo Sample Program in memo directory OpenDialog Component SaveDialog Component Memo Use of OpenDialog Component Sample Program in memo directory 28

29 Memo Sample Program in memo directory Use of SaveDialog Component ActionList Sample Program in actionlist directory 29

30 Sample Program in button_scrollbar directory Vertical ScrollBar Horizontal ScrollBar Sample Program in Radiogroup_panel directory RadioGroup Panel GroupBox 30

31 ScrollBar Sample Program in scrollbar directory 31

Exercises for Delphi Advanced Programming Technology (English Version)

Exercises for Delphi Advanced Programming Technology (English Version) School: School of Information Engineering Department: Department of Electronic and Information Engineering Author: Sun Zhaoyun Exercises